1. Field of the Invention
The present invention relates to a signal receiver which is significantly effective for use with a tuner.
2. Description of the Prior Art
Any conventional signal receivers, in particular, the signal receiver which is provided with tuning circuits using varactor diodes feeds identical voltages to respective tuning circuits, and thus, due to different capacitances between varactor diodes, there is a considerable difference between frequency characteristics of respective tuning circuits. To compensate for this, one of the prior art systems had proposed a specific constitution related to the independent control over respective tuning circuits for maximizing the output of intermediate frequencies by feeding tuning voltages to individual varactor diodes so that the tuning circuits are provided with the best frequency characteristics. This prior art system is expressly disclosed in Japanese Patent Publication No. 58-18008 and presented in the technical publication "COMPUTER CONTROLLED TELEVISION CHANNEL SELECTION AND TUNER ALIGNMENT", written by Daniel Dumont and Arno Neelen; IEEE ICCE85 SESSION V--TV SIGNAL PROCESSING II, DIGEST OF TECHNICAL PAPERS, June, 1985, respectively.
However, the circuit constitution proposed by this prior art system causes the output of the intermediate frequencies to be controlled only in the maximizing direction and seeks maximum power within the output signal bands. consequently, there is no room for identifying whether or not frequency characteristics of respective tuning circuits exactly match ideal characteristics within the output signal. Although the proposed prior art system improves power gain and signal-to-noise (S/N) ratio, signals may be distorted themselves due to inclined frequency characteristics within the output signal bands.